1、 MSS SP-128-2012 Ductile Iron Gate Valves Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 281-6671 E-mail: standardsmss-hq.org MSS www.mss-h
2、q.org MSS STANDARD PRACTICE SP-128 i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 106 and the MSS Coordinating Committee. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an effective, cle
3、ar, and non-exclusive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirements and is intended as a basis for common practice by the manufacturer, the user, and the general public. The existence of an MSS Standard Practice does not in itself precl
4、ude the manufacture, sale, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor does it undert
5、ake to enforce or certify compliance with this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated otherwise within
6、 this MSS Standard Practice, other standards documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex C). This Standard Practice shall remain silent on the validity of those other
7、 standards of prior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not be held respo
8、nsible for identifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to be essential
9、to the understanding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include mandatory requirements. U.S. customary
10、units in this Standard Practice are the standard; SI (metric) units are for reference only. Substantive changes in this 2012 edition are “flagged” by parallel bars as shown on the margins of this paragraph. The specific detail of the change may be determined by comparing the material flagged with th
11、at in the previous edition. Non-toleranced dimensions in the Standard Practice are nominal, and, unless otherwise specified, shall be considered “for reference only.“ Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracted from MSS SP-128-2012 with permis
12、sion of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemination is prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fi
13、ttings Industry Inc. All rights reserved. Originally Approved: February 2006 Originally Published: July 2006 Current 2012 Edition Approved: July 2011/May 2012 Current 2012 Edition Published: May 2012 MSS is a registered trademark of the Manufacturers Standardization Society of the Valve and Fittings
14、 Industry, Inc. Copyright , 2012 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-128 ii TABLE OF CONTENTS SECTION PAGE 1 SCOPE . 1 2 VALVE TYPES, CLASS, AND SIZE 1 3 PRESSURE-TEMPERATURE RATINGS . 1 4 MATERIALS 2 5 DESIGN .
15、 2 6 WORKMANSHIP . 5 7 TESTS . 5 8 MARKING 5 9 PAINTING 5 TABLE 1 Pressure-Temperature Ratings for ASTM A395/A395M, Non-Shock, psi . 6 2 Pressure-Temperature Ratings for ASTM A536, Non-Shock, psi 6 3 Test Duration, Minimum . 6 B1 Pressure-Temperature Ratings for ASTM A395/A395M, Non-Shock, bar . 10
16、B2 Pressure-Temperature Ratings for ASTM A536, Non-Shock, bar 10 FIGURE A1 Rising Stem, Solid-Wedge Gate Valve, Type I . 7 A2 Non-Rising Stem, Solid-Wedge Gate Valve, Type I . 7 A3 Rising Stem, Solid-Wedge, Resilient-Seat Gate Valve, Type II . 8 A4 Non-Rising Stem, Solid-Wedge, Resilient-Seat Gate V
17、alve, Type II . 8 A5 Rising Stem, Double-Disc, Parallel-Seat Gate Valve, Type III . 9 A6 Non-Rising Stem, Double-Disc, Parallel-Seat Gate Valve, Type III 9 ANNEX A Valve Types Figures A1 through A6 7 B Pressure-Temperature Ratings in (SI) Metric Units 10 C Referenced Standards and Applicable Dates .
18、 11 MSS STANDARD PRACTICE SP-128 1 1. SCOPE 1.1 This Standard Practice provides requirements for ductile iron gate valves with flanged, threaded, mechanical joint, and push-on end connections. 1.2 These valves are suitable within the sizes and pressure temperature ratings specified herein for genera
19、l purpose service. 1.3 This Standard Practice also includes, directly or by reference, stipulations for chemical and physical properties of materials and dimensions of end connections in common use. 1.4 This Standard Practice covers ductile iron gate valves with Cold Working Pressure (CWP) and Class
20、 designated ratings. 2. VALVE TYPES, CLASS, AND SIZE 2.1 Valve Types Valve types covered herein are illustrated in Figures A1, A2, A3, A4, A5, and A6 in Annex A(1). Type I Solid-Wedge, Metal-Seat Gate Valve (See Figures A1 and A2) Type II Solid-Wedge, Resilient-Seat Gate Valve (See Figures A3 and A4
21、) Type III Double-Disc, Parallel Metal-Seat Gate Valve (See Figures A5 and A6) 2.2 Operation Manual valves shall be designed for non-rising stem (NRS) or outside screw and yoke (OS with stub threads conforming to ASME B1.8, or 60-degree threads approximating the stub form. Minor variations shall be
22、permitted. The threads shall be precision cut or formed to fit the engaging member. b) Outside-screw and yoke stems shall be of sufficient length so as to be at least flush with the top of the yoke nut after the disc wedges have worn into their lowest position and the valve is fully closed. The desi
23、gn shall be such as to prevent the wedges or disc from leaving the stem or the stem from turning during the operation of the valve. c) Non-rising stem gate valves having separate stem engaging members shall be so designed as to prevent rotation or pulling out of the disc or wedge. 5.12 Backseat When
24、 a backseat is provided, repacking the valve while it is pressurized is not recommended. 5.13 Handwheels Handwheels shall be of the spoke type only. Webbed or disc type are not permissible. Handwheels shall be marked with the direction for opening the valve. 5.14 Bypass and Drain Connections Unless
25、otherwise specified by the purchaser, bypass and drain connections shall be in accordance with MSS SP-45. MSS STANDARD PRACTICE SP-128 5 6. WORKMANSHIP 6.1 Castings All castings shall be clean and sound, without defects that will impair their service. Plugging, impregnating, welding, or repairing of
26、 structural defects is not permitted. 6.2 Valve Parts Valve parts shall be designed and manufacturing tolerances set so as to provide interchangeability in the product of any one manufacturer between units of the same NPS, class, type, and design, except for the individual fit of the wedge or disc i
27、n the body. 7. TESTS 7.1 General A pressure test shall be made on all completed valves prior to shipment by the manufacturer. 7.2 Shell Test Valves in the partially open position with both ends sealed shall be subjected to hydrostatic or gas-test pressure of at least 1.5 times the cold working press
28、ure. Double-disc gate valves may be tested between the gates in the closed position. Visible leakage through the pressure boundary walls or body-bonnet joint shall be cause for rejection. Leakage through the stem packing or stem seals shall not be cause for rejection. Test pressure shall be maintain
29、ed for the duration specified in Table 3. Caution: Safety precautions must be taken when gas is used. 7.3 Hydrostatic Seat Test Valves shall be subjected to a hydrostatic seat test at not less than the rated working pressure. The test pressure shall be applied successively on each side of the closed
30、 gates, and the opposite side shall be checked for leakage. As an alternative method for double-disc gate valves, the pressure may be applied inside the body or bonnet with discs closed and both sides checked for leakage. The maximum permissible leakage rate for metal-seated valves shall be 10 ml/hr
31、/NPS. Leakage is not permitted for resilient-seated gate valves. Test pressure shall be maintained for the duration specified in Table 3. 7.4 Gas Seat Test At the manufacturers option, a gas seat test, at a pressure not less than 80 psi (5.5 bar), may be used in lieu of the Hydrostatic Seat Test (se
32、e Section 7.3). The gas pressure shall be applied as specified for the hydrostatic seat test. The maximum permissible leakage rate for each gate seat shall be 0.1 std ft3/hr/NPS (2.8 1/hr/NPS). The pressures shall be maintained for the durations specified in Table 3. Caution: Safety precautions must
33、 be taken when gas is used. 8. MARKING 8.1 Marking shall conform to MSS SP-25. 9. PAINTING 9.1 The painting of finished valves shall be optional with the manufacturer, unless otherwise specified by the purchaser. Ferrous seating-surfaces for resilient-seated gate valves shall comply with Section 5.8
34、 (c). MSS STANDARD PRACTICE SP-128 6 TABLE 1 Pressure Temperature Ratings for ASTM A395/A395M, Non-Shock, psi Temperature (F) ASME B16.42 Class 150 ASME B16.42 Class 300 NPS 2 24 NPS 2 24 -20 to 100 250 640 200 235 600 300 215 565 400 200 525 500 170 495 600 140 465 650 125 450 TABLE 2 Pressure Temp
35、erature Ratings for ASTM A536, Non-Shock, psi Temperature (F) ASME B16.1 Class 125 ASME B16.1 Class 250 NPS 2 12 NPS 14 24 NPS 30 48 NPS 2 12 NPS 14 24 -20 to 150 200 150 150 500 300 200 190 135 115 460 280 225 180 130 100 440 270 250 175 125 85 415 260 275 170 120 65 395 250 300 165 110 50 375 240
36、325 155 105 355 230 350 150 100 335 220 375 145 315 210 400 140 290 200 425 130 270 450 125 250 TABLE 3 Test Duration, Minimum Size Shell Test (Seconds) Seat Test (Seconds) NPS DN 2 12 14 24 30 Larger 50 300 350 600 750 Larger 30 60 180 30 60 120 MSS STANDARD PRACTICE SP-128 7 ANNEX A Valve Types Fi
37、gures A1 through A6 RISING-STEM, SOLID-WEDGE GATE VALVE, TYPE I 1 Body 2 Wedge, Closure Gate 3 Seat Ring 4 Bonnet, Cover 5 Bonnet Bolts, Studs, ANSI/ASME B1.1-2003 (R2008) Unified Inch Screw Threads, (UN and UNR Thread Form) B1.5-1997 (R2009) Acme Screw Threads B1.8-1988 (R2011) Stub Acme Screw Thre
38、ads B1.20.1-1983 (R2006) Pipe Threads, General Purpose (Inch) B16.1-2010 Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250 B16.10-2009 Face-to-Face and End-to-End Dimensions of Valves B16.42-2011 Ductile Iron Pipe Flanges and Flanged Fittings, Classes 150 and 300 B18.2.1-2010 Squ
39、are, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series) B18.2.2-2010 Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling Nuts (Inch Series) ASTM Standard Specification for: A193/A193M-11a Alloy-Steel and
40、Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications A194/A194M-11 Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both A307-10 Carbon Steel Bolts and Studs, 60 000 psi Tensile Strength A395/A395M-99(2009
41、) Ferritic Ductile Iron Pressure-Retaining Castings for Use at Elevated Temperatures A536-84(2009) Ductile Iron Castings AWWA; ANSI/AWWA C110/A21.10-08 Ductile-Iron and Gray-Iron Fittings for Water C111/A21.11-07 Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings C550-10 Protective Epo
42、xy Interior Coatings for Valves and Hydrants MSS SP-6-2012 Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings SP-25-2008 Standard Marking System for Valves, Fittings, Flanges, and Unions SP-45-2003 (R 2008) Bypass and Drain Connections SP-98-2012 Pr
43、otective Coating for the Interior of Valves, Hydrants, and Fittings MSS STANDARD PRACTICE SP-128 12 ANNEX C (Continued) Referenced Standards and Applicable Dates The following organizations appear on the previous page of this Annex: ANSI American National Standards Institute, Inc. 25 West 43rd Stree
44、t, Fourth Floor New York, NY 10036-7406 ASME American Society of Mechanical Engineers (ASME International) Three Park Avenue New York, NY 10016-5990 ASTM ASTM International 100 Barr Harbor Drive, P.O. Box C700 West Conshohocken, PA 19428-2959 AWWA American Water Works Association 6666 West Quincy Av
45、enue Denver, CO 80235-3098 MSS Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, VA 22180-4602 Listing of MSS Standard Practices (as of May, 2012) TITLE SP-6-2012 Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges o
46、f Valves and Fittings SP-9-2008 Spot Facing for Bronze, Iron and Steel Flanges SP-25-2008 Standard Marking System for Valves, Fittings, Flanges, and Unions SP-42-2009 Corrosion Resistant Gate, Globe, Angle and Check Valves with Flanged and Butt Weld Ends (Classes 150, 300 & 600) SP-43-2008 Wrought a
47、nd Fabricated Butt-Welding Fittings for Low Pressure, Corrosion Resistant Applications (Incl. 2010 Errata Sheet) SP-44-2010 Steel Pipeline Flanges (incl. 2011 Errata Sheet) SP-45-2003 (R 2008) Bypass and Drain Connections SP-51-2012 Class 150LW Corrosion Resistant Flanges and Cast Flanged Fittings S
48、P-53-1999 (R 2007) Quality Standard for Steel Castings and Forgings for Valves, Flanges, and Fittings and Other Piping Components Magnetic Particle Examination Method SP-54-1999 (R 2007) Quality Standard for Steel Castings and Forgings for Valves, Flanges, and Fittings and Other Piping Components Ra
49、diographic Examination Method SP-55-2011 Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Visual Method for Evaluation of Surface Irregularities (ANSI-approved American National Standard) SP-58-2009 Pipe Hangers and Supports Materials, Design, Manufacture, Selection, Application, and Installation (incorporates content of SP-69, 77, 89, and 90) (ANSI-approved American National Standard) SP-60-2012 Connecting Flange Joints between Tapping Sleeves a
